Behavioural response of wild rodents to the calls of an owl: a comparative study

Effective anti-predator defence mechanisms depend on efficient recognition of possible predators. However, nocturnal aerial predators, such as owls, present very few stimuli to enable their detection by potential prey. The most prominent of these are their territorial calls which are believed to provide sufficient stimuli to activate anti-predator defence mechanisms in species heavily predated upon by owls. To test this hypothesis, the behaviour of voles (Microtus socialis), dormice (Eliomys melanurus), jerboas (Jaculus jaculus), and spiny mice (Acomys cahirinus) was analysed during and following exposure to playback of tape recorded calls of the tawny owl (Strix aluco). In response, voles crouched, and retreated to a small burrow present in the test arena; dormice also reduced the distances they travelled in the arena, and spent an increased amount of time around the burrow; jerboas crouched and froze during the playback of the owl call but not thereafter; spiny mice, however, displayed enigmatic behaviour in apparently ignoring the owl calls. The results, which demonstrate an induction of defensive behaviours to recorded owl calls, support the results of others who have examined the effects of exposing wild rodents to live owls.